A photosensitive resin composition comprising, as a carrier resin component, an elastomer such as a chlorinated rubber, a styrene-butadiene block copolymer, a polyurethane or the like and containing an ethylenic unsaturated compound and a photo-polymerization initiator is useful as a printing plate material for flexography due to the characteristics of the elastomer. Many such compositions have been proposed, for example, in U.S. Pat. Nos. 2,948,611, 3,024,180, Japanese Patent Publication No. 51-43374, etc.
Such solid, photosensitive resin plate materials need to be developed with halogenated hydrocarbons and therefore have problems as causing health injury, environmental pollution, etc. Therefore, the development of solid, photosensitive resin materials for flexographic printing plates is desired. Various proposals for providing solid, photosensitive resin compositions which are developable with water to give printing plates for flexography have been made, for example, in Japanese Patent Publication No. 62-42259, Japanese Patent Laid-Open Application Nos. 61-22339, 63-186232, 5-160451.
However, it is hard for the materials proposed in these to wholly satisfy the raw plate strength and the water developability of printing plate precursors, the flexibility suitable for flexographic printing plates and even the compatibility with aqueous ink which is essentially used in flexography. Therefore, those which are satisfactory for practical use have not yet been obtained. In particular, solid, photosensitive resin materials for flexographic printing plates which can be developed substantially with only neutral water by practical development have not heretofore been obtained.
The present invention has been made in consideration of various drawbacks in such prior art techniques, and its object is to provide photosensitive resin compositions for flexographic printing plates which have high-degree image reproducibility and flexibility suitable for flexography and which have good water developability and good compatibility with aqueous ink.